The invention relates to a skin-coloring preparation, containing a hydroxycarbonyl compound which has self-tanning properties, in a cosmetologically acceptable carrier, which preparation contains at least one colorant which adheres to the skin.
It has been known for some time that compounds which have a keto group ##STR1## preferably hydroxymethylketones, in particular dihydroxyacetone, but also methyl glyoxal, have a self-tanning effect on human skin. This self-tanning effect is essentially based on a Maillard reaction between the keto group of these compounds and the amino acids of the skin.
Moreover, it is known that the hue obtained in this reaction can be further enhanced by adding certain adjuvants.
For example, EP 04 56 545 and EP 05 00 446 propose to employ indole derivatives, which were synthesized to resemble natural melamine, in such formulations. However, since their adhesion to the skin is relatively poor, they must be employed in relatively high concentrations.
According to FR 20 85 208, freckles can be produced artificially with formulations containing dihydroxyacetone and a water-soluble colorant However, the adhesion to the skin is poor, due to the solubility of these colorants in water.
Moreover, it has been proposed to prepare self-tanning formulations (for example U.S. Pat. No. 3,920,808 or U.S. Pat. No. 4,708,865) which contain, besides dihydroxyacetone, unsaturated ketones, for example lawsone or juglone. However, these produce an unnatural-looking, yellowish hue.